Fix jdk-threading-plugin memory leak #7001 (#7003)

CHANGES.md

@@ -31,6 +31,7 @@ Release Notes.
 * Fixed part of the dynamic configuration of ConfigurationDiscoveryService that does not take effect under certain circumstances.
 * Introduce method interceptor API v2
 * Fix ClassCast issue for RequestHolder/ResponseHolder.
+* fixed `jdk-threading-plugin` memory leak.
 
 #### OAP-Backend
 * BugFix: filter invalid Envoy access logs whose socket address is empty.

apm-sniffer/bootstrap-plugins/jdk-threading-plugin/src/main/java/org/apache/skywalking/apm/plugin/jdk/threading/ThreadingMethodInterceptor.java

@@ -48,12 +48,7 @@ public class ThreadingMethodInterceptor implements InstanceMethodsAroundIntercep
     @Override
     public Object afterMethod(final EnhancedInstance objInst, final Method method, final Object[] allArguments,
         final Class<?>[] argumentsTypes, final Object ret) {
-
-        final Object storedField = objInst.getSkyWalkingDynamicField();
-        if (storedField != null) {
-            ContextManager.stopSpan();
-        }
-
+        ContextManager.stopSpan();
         return ret;
     }